Trace Entry Verification Count
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
In a VM/SP operating system, if one has a trace table shared by a number of virtual machines, one needs to insure that entries in the table are valid. The trace table can be put in an area of storage that is shared by all virtual machines that are members of a particular "group". Each trace table entry must include a "header", which identifies the type event causing the trace entry, the length of the trace entry, time and date information, virtual machine identification, and a "Trace Entry Verification Count" (TEVC). When the trace table is full, it "wraps" and is reused from the beginning. The method of allocating "slots" for trace table entries, and the nature of virtual machines in general, allows one virtual machine to reserve a slot for a trace entry and then be interrupted before putting the trace entry into that slot.